I have wondered for years why our universities have not adopted this.
Apache

Probably a few reasons.

1.
Ereaders weren't ready. They still aren't quite ready. And the few that could conceivably be used for schoolwork are the most expensive. See #3.

2.
The publishers of college textbooks would rather make $200 a book than $50. It's true the production costs for the physical books is higher, but their profit margin is still bigger in a system where they can tweak the font and call it a "new edition" every semester and force teachers to use it, thus forcing students to use it. They can't do that with an ebook. I can't recall the number, but the percentage of textbooks that have gone digital is a small fraction. Conversely, the percentage of commercial books being released with a digital version available, or being digitized is shooting through the roof. College textbook publishers resisting, because it hurts their margins.

3.
A lot of colleges these days have had their budgets slashed to bare bones, with public schools losing as much as 50% of their funding over the last decade or so. Simultaneously, enrollment is spiking due in part to the Echo Boomers and in part to desperate unemployed career people trying to get extra training in the hopes it will help them find a job sometime before 2015.

In an environment where both schools and students are going broke, it's hard to imagine how it would be feasible to require every student to get a high-end ereader, or how the school would cover those who can't. It's true the textbooks cost almost as much as the reader, but a lot of students these days simply don't buy the textbooks and try to scrape by as best they can, or buy an "old" edition for a quarter of the money.

Textbook publishers make most of their money on freshman who don't know any better. But by the time they wise up, they're already staring down a mountain of debt and there's no way they're going to blow a couple hundred or more on a cutting edge reader - they're going to keep trying to get by with really old editions or no textbooks at all. And as incoming students get broker, even the freshman will be hard to sway. I was one of the freshman the publishers got, but I know others who simply don't have books.